Can I hold pep boys accountable for my lost tire lock key since they left it on my tire and it fell off while I was driving home?

That would make me wonder if they even tightened the lug nuts!

How do you know they left it on the tire? Maybe they gave it back to you and you just lost it.

Sure. If you can prove it. But you can't.

You did not ensure you got your locking wheel nut key back? Shame on you. They will say you lost it.
Of you know the code buy a replacement if not get a new set of locking wheel nuts and get the old ones removed.

No, because the never TOUCHED your lug nut key. They used their key. You lost your key all by yourself..

http://autorepair.about.com/od/fixityourself/u/path_DIYrepairs.htm?utm_term=car%20maintenance%20and%20repair&utm_content=p1-main-2-title&utm_medium=sem&utm_source=msn&utm_campaign=adid-fbde64ce-6e66-4a6d-b376-f7eff5263c27-0-ab_msp_ocode-7930&ad=semD&an=msn_s&am=phrase&q=car%20maintenance%20and%20repair&dqi=&o=7930&l=sem&qsrc=999&askid=fbde64ce-6e66-4a6d-b376-f7eff5263c27-0-ab_msp